Installation of an aftermarket fuel pump is a very common one for a 4G63, especially when it’s time to turn up the boost and put down some real power. If your 4G63 is experiencing fuel cut, the load on your vehicle has reached beyond the limits of your fuel system as your Injector Pulse With (IPW) is too high.
When your PCM determines that the IPW has reached levels deemed too dangerous for operation, thats when the ECU decides to cut your spark and subsequently your fun. So what to do but to upgrade your fuel system! Let’s begin!
The install of an aftermarket fuel pump in our subject 1998 Mitsubishi Eclipse GSX is straightforward procedure, and can be installed by an above average mechanic.
*** NOTE!! As with all of our installs and walkthroughs, our guides should be used only as a guide. You must use extreme care when working around the gas tank, fumes are highly combustible and can be toxic. Do not use a light that generates heat such as a drop light, and make sure you have someone to help you with this install and to keep an eye on any potential leaks or spills.
First, you must relieve the pressure in your fuel line before disconnecting any lines or working on your fuel system. Disconnect the negative terminal on your battery, open your fuel tank cap and give it a few seconds to air out. It might also be a good idea to open the hatch on your Eclipse to allow for any potential fumes to escape.
Many different pumps exist for this vehicle, ranging from the BBK, Holley and Walbro pumps of the 190, 215, 255 and 300 lph varieties. Today we will be installing a DeatschWerks DW300 Fuel Pump, part number 9-301-0883.
Now, find yourself a flat level surface and jack up the vehicle, while making sure to secure it on jackstands. If you are working on a lift, make sure you have a spare container to catch the fuel that will leak out once we open the line underneath the vehicle.
Get back into the cabin, and push your passenger seat forward to gain more room to the backseat and fuel pump area. Reach back into your back seat and under the front of the seat you will find the 2 release tabs on either side of the seat. Pull those tabs out and now your rear seat should come right out, revealing your fuel pump panel.
Unscrew the 4 screws holding your panel to the frame using a Phillips screwdriver, as well as the one screw holding the wiring loom guides that lead to your fuel pump. Remove the access panel to expose the fuel tank and the pump assembly.
The 2g fuel pump assembly uses metal lines but unfortunately the compressed line that is connected to the top of the assembly is far too difficult to remove from the top of the assembly. Because of this, we recommend taking a pair of snips and cutting a small tab into your chassis.
Done right, this has zero bearing on the structural integrity of your vehicle, and makes the install process much more easier.
Whatever you do, DO NOT cut or modify the hard lines on your fuel pump assembly. These lines are under pressure and the last thing you want is a leak while driving down the road.
Now that you have your tank area notched, you should see the white plastic impact ring that seals your fuel tank and fuel pump assembly. Unplug the wiring harness and disconnect the soft rubber hoses and push them away to gain access to this white ring.
Take a hammer and chisel or flathead screwdriver and gently tap the white compression ring off your fuel tank to crack open the seal on your fuel pump assembly.
Make sure to take extreme care when installing and removing this white ring to prevent any damage to the threads on your fuel tank or the ring itself.
Now get under your vehicle, and follow the hard line back under your fuel tank to locate the fitting we will have to remove. This hose is usually marked red from the factory to indicate that its a fuel line.
Take your 19mm and 14mm wrenches to crack open this line, take care not to twist or pinch the hard lines in question. You might want to have some spare rags or kitty litter at the ready for the gas that will spill out.
Now you are ready to pull out your fuel pump assembly!
Pull the pump out and carefull lay everything out on a piece of cardboard, which will absorb any fuel that is probably still leaking out of your pump or fuel strainer.
Make sure to take care when moving the assembly around, you don’t want to lose any parts or hardware. Now with your Phillips, undo the screw located on the back of the mounting plate, which will free up your pump.
Now your stock pump can be removed, make sure not to damage or lose the plastic orings or seal rings that are connected to the neck of the pump.
A look at the orings and the plastic snap ring that must be transferred to our new fuel pump.
If your pump is a plug and play unit, meaning you have purchased it for use specifically in your 2g DSM then simply swap over the orings and plastic oring and plug in the in-tank fuel harness. For those using a pump NOT designed for plug and play usage, you can unclip or cut the harness for a more direct installation.
The wiring for the in tank fuel harness is very straightforward, Blue is positive, black is negative. Cut and strip the wires in preparation of installation.
You can elect to crimp some connectors onto the wires for installation, and then clamp them down on your replacement pump.
Now put the entire fuel pump back into place on the assembly, take care to transfer any and all hardware including the new sock / strainer and circlip that retains the strainer.
Now slide the entire pump assembly back into your fuel tank, with the fuel tank floater slid in first as to prevent any damage to the floater or fuel level sender. The fuel level sender is the the plastic bulb attached to the arm of your fuel pump assembly.
** Remember to make sure the black rubber grommet that is in the tank is there and firmly in place before screwing on the white compression ring. Failure to do so will prevent your car from starting.
Pressing firmly down on the white oring, start screwing the oring back in. use the hammer and screwdriver trick again to make sure that you have it nice and tight. Reattach all connectors, fuel lines, the 19mm / 14mm junction under the car, the access panel, 5 screws and your rear seat and lower the car.
Because there is no fuel in the line or pressure in the system it may take a few cranks before your car starts back up. When you have your car started, watch the area directly under the 19/14mm junction to ensure there are NO LEAKS.
You are done! Enjoy your new fuel pump!!
Commonly asked questions regarding the fuel pump
Q: Is the “strainer” my fuel filter?
A: No, your 2g DSM fuel filter is located on your firewall, behind your motor.
Q : I followed your instructions but I smell a lot of gas, is there a problem?
A: Depending on how full your gas tank was at the time of install, some or no fuel may have leaked out onto your tank surface, if this is the case, give it a few days, it should clear up. If this isnt the case, make sure to have the white plastic oring nice and snug, and the pump tightly sealed.
Q : I finished the install and my car took a long time to start, is there something wrong?
A: No, you relieved quite a bit of fuel and pressure from the lines, it may take a few times to restore this pressure in your fuel rail and start the car.
Q: Is there a way I can test my fuel pump?
A: Disconnect the fuel pressure regulator (FPR) line that runs back to your firewall from your fuel rail. With your parking brake on, car in neutral have someone crank the car to see if fuel is being pumped into your rail.
Q: Why is it bad to drive my car on empty all the time?
A: Because driving your car on low gas can ruin the life of your fuel pump and fuel components. If you are low on gas the rest of the space in your tank is taken up by air, which contains water vapors. When it cools down this moisture can condense on the sides of your fuel tank and other metal components, which will end up rusting the insides of your tank, mix with your fuel or cause all kinds of other issues.
Enjoy your fuel pump!
- Pro Street Staff